Heretofore, in the field of CMOS image sensors, there has been known a column ADC technology for obtaining AD conversion results, which are resistant to exogenous noise.
Japanese Laid-Open Patent Publication No. 09-238286 discloses that an amplifying solid-state image sensing device, which incorporates a plurality of analog-to-digital converters with a noise reducing function (integrating analog-to-digital converters) therein, latches and then successively selects digital signals from the analog-to-digital converters.
Heretofore, there has also been known a TOF (Time Of Flight) method for measuring the distance up to a subject by detecting light reflected from a subject that is illuminated by an illuminating unit. Since pixels, which detect the reflected light, also receive ambient light such as sunlight in addition to reflected light, it is necessary to subtract the amount of photoelectrons, which are generated by the pixels as a result of ambient light, from the amount of photoelectrons that are generated by the pixels due to both reflected light and ambient light.
Japanese Laid-Open Patent Publication No. 2008-089346 discloses a solid-state image sensing device for generating the difference between a plurality of stored photoelectrons. More specifically, the disclosed solid-state image sensing device includes a plurality of capacitors and a plurality of photoelectron storage units for storing photoelectrons generated from light detected by pixels. The photoelectron storage units and the capacitors are selectively rendered electrically conductive so as to cause the capacitors to store photoelectrons representing the difference between the photoelectrons stored in the photoelectron storage units. Thus, the solid-state image sensing device can extract from the capacitors differential components of the photoelectrons stored in the photoelectron storage units.